1. Field of the Invention
This invention relates to a printing apparatus having a plate cylinder for supporting printing plates mounted peripherally thereof, and a plate feeder disposed between the plate cylinder and a storage cassette storing an unexposed plate stock for holding and transporting printing plates to the plate cylinder. This invention relates also to a printing plate mounting method for mounting printing plates on the plate cylinder.
2. Description of the Related Art
A known printing apparatus as noted above is described in Japanese Unexamined Patent Publication No. 11-77965 (1999), for example.
The apparatus described in the above publication includes a forward end clamp mechanism arranged on the plate cylinder and having a clamp and a clamp seat. The clamp and clamp seat hold therebetween the forward end of a printing plate mounted peripherally of the plate cylinder. This apparatus further includes a squeeze roller movable between a squeeze position adjacent the surface of the plate cylinder for squeezing, against the periphery of the plate cylinder, the printing plate having the forward end thereof held between the clamp and clamp seat of the forward end clamp mechanism, and a standby position spaced away from the surface of the plate cylinder. Thus, the above apparatus can mount the printing plate peripherally of the plate cylinder in an extended state, without slackening the printing plate.
However, where a printing plate formed of a highly elastic material is used, the plate can free itself from an extended state and become slack after being pressed against the peripheral surface of the plate cylinder by the squeeze roller in the apparatus described in Japanese Unexamined Patent Publication No. 11-77965 (1999). Such slackening is notable particularly with printing plates formed of a highly elastic material or having curls.